Basement Wall Waterproofer Review: Super Thoroseal
Two years ago, we waterproofed over 1000 square feet of cinder block wall in our mostly-underground basement. We applied Super Thoroseal to 500 sq. ft., and SunnyDry Foundation Waterproofer to the other 500 sq. ft. (Follow that SunnyDry link for our initial review of their product, which is still holding up well today).
When we ran that initial review, we promised a follow-on article with a review of Super Thoroseal’s performance, but like so many things, it fell off the plate. So here’s that review, two years later.
What is Super Thoroseal?
To bring you back up to speed, Super Thoroseal is a portland-cement based waterproofer that is sold in 35 lb., five gallon buckets at a variety of stores–most notably Home Depot, where we purchased it. Super Thoroseal is suitable for a variety of waterproofing applications, including above and below grade concrete and masonry waterproofing. It cannot be applied to painted surfaces.
Super Thoroseal claims a 200 PSI waterproofing capability, nearly 10 times the standard waterproofing available from paint-based solutions like traditional Dry Lok. (Note: Dry Lok now offers a portland cement based solution as well).
Installation method is extremely important as the product will not work as advertised if the instructions for wall prep and application are not followed to a “T”. I’ll repeat this because it’s important: installation method is very important. Do not short cut the installation or your seal may fail prematurely. Alright, enough of that. Here’s how to apply it:
How to Apply Super Thoroseal
Wall Prep: The walls must be cleaned of debris and efflorescence, wet (as in, with a hose), and the temperature must be above 40 degrees. You can see Thoro’s online instructions & product sheet for more information on application specs and performance.
Mixing: Measure and add the appropriate amount of water to a separate five-gallon bucket. Do not add too much or too little water. Add the Super Thoroseal powder and mix with a suitable drill & mixing paddle until it becomes a pancake batter consistency. Do not try to mix Super Thoroseal by hand, you will not be able to get a good mix. Super Thoroseal stays spreadable for about 30 minutes. Do not pour water into the Super Thoroseal bucket. The water must be poured into a separate bucket and the powder dumped on top!
Application: Wet the walls with a garden hose and apply the mixed batter using a tampico fiber brush (also available at the big box). Cover the walls thoroughly. Full seal occurs after two coats. Note: you must apply both coats within a 24-48 hour period. Do not let the first coat stand for more than 48 hours or the second coat will not bond and seal well.
Super Thoroseal Coverage & Price
One five-gallon bucket runs about $25 at the local big box. Coverage is up to 105 sq. ft. and requires two coats to achieve watertight seal. We found Thoro’s coverage claims on the bucket to be accurate.
Super Thoroseal Water Sealing Performance
We’re pleased to report that after two years, Super Thoroseal is living up to its promise. We have no leaks in the basement, and recommend this product to folks looking to seal their own basements. If we ever do experience an issue, we’ll update this article with the bad news.
Update 10/16/09: Last night, we examined the wall in one of the corner areas on the wall and noticed a small section (about 2×2 inches) of the ST had de-laminated from the wall. It appeared that the Super Thoroseal in this area didn’t form a good bond and was a bit ‘powdery’ – it wasn’t well mixed. I don’t blame this on ST and actually believe it may have been an error in our installation process (the first coat we applied didn’t follow my instructions here exactly, and we may not have mixed it well because it was our first try). The good news is the issue appears isolated and not characteristic of the rest of the wall. Also, there’s still no moisture in the area despite the rain we’ve had, which leads me to believe some of the ST is still clogging the pours of the concrete. I will continue to update this post if we have any other issues.
What do you think? Do you have any experience with Super Thoroseal? Leave your thoughts in the comments section.
P.S. There’s been a lot of news lately about changes to FTC regulations that require bloggers to disclose any form of compensation they receive for reviewing products. Just so you know our policy: we always let you know if a company gives us a product (vs. one that we bought off the shelf and reviewed on our own). If we don’t mention that a product was provided to us, it means that we bought the product with our own cash (as is the case in this review of Super Thoroseal).
Comments & Conversation on this Article...
23 Responses to Basement Wall Waterproofer Review: Super Thoroseal
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October 6th, 2009 12:43 pm
Wow, this review was so educational! I had no idea where to even begin with the process of using a waterproofer. Sadly, I don’t think this will work for my basement. But I’m enjoying learning about what’s available. Thanks for the great article!
October 6th, 2009 9:39 pm
Kelli, glad you enjoyed it! We’re very pleased with Thoro’s product…
October 15th, 2009 4:48 pm
Great information. Thanks for the review! I was skeptic of using Super Thoroseal ($25 x pail) because the price difference between this product and Drylok ($100 x pail). I just applied the second coat and hope; as you, state that it works great!
Thanks again,
October 16th, 2009 11:29 pm
H – We’re still happy with the product. I will say that in one 2 inch by 2 inch area on the basement wall we recently had a piece delaminate. Now, that’s not characteristic and when we applied the Super Thoroseal, we didn’t follow my instructions here 100% …
In fact, we applied the first coat and then let it sit for a week. We then applied two more coats. We still aren’t getting moisture in that location, I suspect because the ST seeped into the pours of the concrete.
I think you’re real safe going with ST vs. Drylok — The Drylok product that is in the same size barrell gets a little more coverage, but doesn’t seal as tight as ST… Just make sure to follow the instructions. We’ve talked to a number of local contractors and they trust ST for this type of sealing job.
October 17th, 2009 11:27 pm
Wow! Love the article. Hubby and I have a huge two stall commercial truck garage on our property and have been debating if we should attempt to build a home out of it. One of our main concerns is that when the garage was built 30-35 years ago, the previous owners did not lay any type of moisture barrier before pouring it’s concrete floor. The drainage is awful and the floor is always wet. Two rooms were built into the back of the garage and they are full of mold. (as I’m sure the trusses and rafters are also). This garage is 32′ x 48′ with 12′ ceilings… This (in my humble opinion) would make a great start for a house!
Thanks for the review!!!
Tammy OHagan
November 12th, 2009 11:19 pm
Thanks for taking the time to post such valuable information. We, too, are preparing to seal a block wall and found your advice to be most helpful. I notice that with most of these products, there is a need to remove any efflorescence. Did you have to do that, and if so, how did you do it? We’ve seen a variety of conflicting advice on the subject.
January 19th, 2010 7:33 pm
RE: Basement Wall Waterproofer Review: Super Thoroseal
Hello,
Loved the review on the Thoroseal and SunnyDry waterproofing. How is the SunnyDry holding up after 2 years?
Thanks!
January 19th, 2010 11:49 pm
Hi TIm,
SunnyDry is also performing well.
In November, we had the walls insulated with closed cell foam, permanently closing up our work, so it will be hard for me to monitor further progress unless something really goes wrong (which I certainly hope it doesn’t).
Can’t say it enough – prep instructions are important.
January 23rd, 2010 10:26 am
Any advice on basement floor sealer. Will this work on the floor as well?
Cole
January 31st, 2010 9:36 pm
Cole, this won’t work for basement floors… Unfortunately, I don’t know a good product for that. Have you looked at something like Schluter’s Ditra? What are you planning for a final walking surface?
February 6th, 2010 5:11 pm
i have cut back the existing plaster and render back to the brick/cement block. Should I apply the Thoroseal onto the brick/cement block or between coats of new render? and what plaster finish should I use
February 8th, 2010 12:11 am
Derek,
ST should be applied directly to the cement/brick. Note that you can’t apply anything directly to the ST after you waterseal with it (e.g., no painting, plaster, etc). You will have to frame out a finished wall.
Fred
February 11th, 2010 11:39 am
My question is i did not see on the instructions for ST you had to apply second coat within 48 hours. I have first on so far concrete wall but its close to being 48 hours and plus. Is this going to be worth putting/attempting second coat of ST or is there an other product to put over ST for a second coat? Please Advise
Thank you
Lou..
March 24th, 2010 10:31 am
After this winter we had here in the Philadelphia area, we have numerous small cracks in our stucco finish. Our contractor wants to paint/cover the small cracks with ST. We are looking to paint the house later this summer. Is this a good idea? Please let me know.
April 13th, 2010 4:25 pm
I had thoroseal recommended to me by a mason for waterproofing decaying stucco over cinder blocks and for cement floors. Both surfaces are painted and that is obviously a BIG issue.
I spoke with the company and many of the elements of the powder are carcinogenic-how did you all deal with this? did you move out of your homes. It was part of the EPA superfund cleanup-so I am worried about kids and dogs and ourselves being in the house.
If we cannot use this this product for all of the above stated reasons, what do you recommend for waterproofing? Are all of these mixtures carcinogenic?
Thanks for your help.
Harriet
May 14th, 2010 11:09 am
I want to seal my cinder block basement wall. There is a white salty-like substance coming through the wall. I’ve been told it is lime. Will Thoroseal stop this? Also the people I bought the house from painted the walls with I believe to be a ceiling paint. What must I do to use thoroseal? Thank you for your attention. Charlie.
May 22nd, 2010 11:10 am
Hi,
We had all 4 walls of our foundation replaced about 3 years ago. Unfortunately, the split faced block used above the ground level was defective( an inappropriate “lighter” mix was used, and after many applications of clear water repellant on the outside, the contractor assured us that thoroseal, applied inside was the best choice to stop the walls from becoming saturated every time rain hit the outside, above ground, block. The first area that it was applied to was obviously not mixed properly- it looks all uneven, and very “thick”, also it was applied to dry walls. In these ares there is staining appearing, that looks “wet” and discolored, but is dry to the touch. I am concerned that the application was botched, and am wondering if there is any way to remove this stuff and reappply it, or, is there any way to “fix” what was done? We are at our wits end, as this job cost us $55,000.00 and a load of headaches. Any thoughts?
May 22nd, 2010 1:18 pm
I am wondering what happened to all of the advice that was being given by the website owner for all of us who don’t know what to do to wateproof our basements. I think this is a great forum, but if no one tells us how to handle our issues we are just venting the same issues to each other.
Thanks for listening.
June 4th, 2010 11:01 pm
My mom’s fixed basement just got about 5 inches of water in it due to the bad flood that just recently happened in our area. We have to take down her paneling and redo tile on her floor. We had someone come in and quote us around 1400.00 to put thoroseal on her walls. Is this a good idea? He says he can make it decorative??
June 5th, 2010 6:21 am
Mary,
I don’t think thoroseal will stop water from pouring in… it seems to me (it is on our walls now) that it is better suited for a “dampness” of the walls, or small crack repair. We had our contractor apply it, and, unfortunately, the first day it was not mixed properly, so the first walls they did are not reacting well, in fact, water stains are on those areas. Proper mixing and application seem to be VERY important. As for the price, I am not sure what labor cost are where you are, but you may want to do some research-Home Depot sells the stuff, however, like I said, application and mixing are the key, so it may be worth paying an experienced person to do this for you. I am just a homeowner, but this is my opinion- we do have it on our basement walls. Hope this helps!!
August 6th, 2010 9:38 pm
I used thoroseal on a basement wall it was some block and some poured concrete, it was painted in a lot of areas but we cleaqned it well and applied as directions said, we did two coats, and im telling you this was the driest basement ever and before that this basement was damp and wet. i miss that base ment so much. Thoroseal beats anything, just prep area wet walls and mix with paddle mixer and pancake mix consistancy . best investment for a basement you can do , been recommending thoroseal for years. i dont know why mine work over paint, didnt remember it saying that, i have painted walls now and im gonna try it. good luck
August 31st, 2010 4:05 pm
Having been in the commercial waterproofing business for a number of years I can honestly say that I would not rely on any waterproofing system that is applied to the opposite side of the wall to which the water is pressing against. Waterproofing should always be on the same side of the wall as the water. Next, avoid using anything other than concrete for a wall you wish to waterproof. Stick to products that remain indefinitely elastic and pliable such as rubberized asphalt. Typical manufacturers are Laurenco or Gaco Western LM60. Follow their installation guidelines and you should be all set. As for Thoroseal I have used it to reduce pourosity of a substrate prior to applying the rubberized asphalt products, but never alone for preventing water penetration. For the record I have worked on buildings that are over 40 feet into the ground. Hope this helps
August 31st, 2010 4:25 pm
For those of you with a concrete block wall for a basement your in a real pickle. Best bet is to dig all the way around the house and apply a rubberized asphalt product to a clean substrate then install drain board such as Henry DB200S and new drain tile wrapped in filter fabric and backfilled with pea gravel. Tie the drain system to a pump and slope the finished grade away from the house. Alternatively, you could drill either through the wall or down through the dirt and inject a hydrophobic material to create a curtain of water resistant material. This is a specialty trade and can cause the wall to crack due to the added pressure on the exterior of the wall. You need someone who has a substantial amount of experience to do this type of work, and I would check with a number of commercial waterproofers in large metro areas to find out who to use. Don’t try and find them in the Yellow pages. If you have a concrete wall that is leaking at a crack or a joint in the wall you can inject the crack with a product that expands to seal the joint. This is also a specialized trade and you should seek the advise of a professional commercial waterproofer working in a large metro area for the proper experience. Lastly, if you haven’t installed a commercial grade waterproofing system and your basement has real water intrusion problems you should avoid installing a finised basement using carpet and insulated stud walls. If you really want a finised basement stick to products like tile for the floor and a breathable paint like TNEMEC for the walls or faux stone that is glued to the wall. Use throw rugs over the tile if you want something softer on the floors. Otherwise, you risk creating the perfect enviroment for Black Mold.
PS: The black stuff your cheapskate builder bought at the local home center doesn’t count as Commercial Grade Waterproofing. To do it right takes planning and attention to detail. You should also be careful of fumes and fire when working with this stuff.